Secondary refrigeration system



Dec. 25, 1951 LA MAR S. COOPER SECONDARY REFRIGERATION SYSTEM Filed May 25, -1948 Inventor: L ,a lVlar` Cooper,

l-li5 Attorney.

Patented Dec. V25, 1951 SECONDARY REFRIGERATION SYSTEM i Mar S. Cooper, Cedar Rapids, Iowa, assignor to General Electric Company, a corporation of l I New York Application May 25, 1948,` Serial No. 29,125

' 'invention relates to refrigerators and more particularly'tol'rcfrigerators employing a' plurality of evaporators.

provided of such a nature as to secure a desirable 'humidity under low ,ambient temperature and no load conditions, it is sometimes found that under' higher 'ambient conditions or under a heavy food or door opening load an excessively high humidity' may' develop ,in the food storage compartment.A Thus a. -refrigerating arrangement which aintains an 'atmosphere of the desired humidity in the foodsto'rage compartment when the ambient temperature is in the order of'70'degrees Ffand when' thereare no door openings or added' food load may result in an excessivelyhigh humidity and in excessive condensationofwaterf' vapor or sweating in the food storage compartment when the ambient temperature is of the orderv of -100 degrees F. and when there are frequent door openings and heavy food load. 'I By 'my invention this condition is avoided and a desirable humidity maintained under varying load and ambient temperature conditions -by providing a plurality 'of properly disposed. evaporators oi'- different re- 'frigerating capacities and operating characterrefrigeration during no' load, low ambient temperature conditions and the other evaporator automatically becomes effective during heavy load, high ambient temperature conditions.

It is a further object of my invention to prolvide a refrigerator including a secondary refrigerating system' having two evaporating portions and a common condensing portion and including an improved arrangement for automatically supplying refrigerant from the ycommon condensing portion to either' of the evaporating portions. Furtherobjects'and'ladvantages' of myfinven- 11 Claims. (Cl. (i2- 125) tion will become apparent as the following description proceeds and the featuresof novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming part of this specification.

For a better understanding of my invention reference may be had to the accompanying drawing in which Fig. 1 is an elevation view, partly in section, of a refrigerator cabinet illustrating my invention; Fig. 2 is a diagrammatic representation of the refrigerating system shown in Fig. 1; Fig. 3 shows a modified form of my invention; Fig. 4 shows another modified form of my invention; and Fig. 5 shows still another modified form of my invention.

Referring to Fig. 1, there is shown a refrigerator cabinet I including a freezing compartment 2 formed by a metal liner 3 and a food storage compartment l formedby a metalliner 5. Access openings for the freezing and food storage compartments are covered by doors 6 and 1 respectively. Suitable insulating material 8 of low thermal conductivity is arranged within the cabinet I about the compartments 2 and 4.

The freezing compartment 2 is refrigerated by a primary evaporator formed by tubing 9. This tubing is secured to the exterior of the liner I of the freezing compartment. Liquid refrigerant is supplied to the primary evaporator from any conventional mechanical refrigerant condensing unit (not shown). This primary evaporator operates at a temperature in the neighborhood of 0 F.

The food storage compartment l is refrigerated by a secondary refrigerating system. The secondary refrigerating system includes an evaporating portion or evaporator lo, an evaporating portion or evaporator Il, and a common conular time, as a result of heat extracted from the food storage compartment l. The vaporized refrigerant passes to the condensing portion i2 where it is condensed, and the liquid refrigerant then flows to one of the evaporating portions |0 or Il. The condensing portion l2 is arranged in heat exchange contact with the tubing 9 of the primary evaporator and heat is extracted by the primary evaporator from the refrigerant vapor in the condensing portion I2 to effect `condensation thereof.

The evaporatingA portions I and II yare arranged on the exterior of the liner of the food storage' compartment in such a manner as to obtain the desired humidity conditions within the food storage compartment 4. The evaporating portion Il is secured in heat exchange contact with the lower portion of the liner 5. The evaporating portion I0 is secured in similar heat exchange contact with the upper portion of this liner. Either or both of these evaporating portions may extend not only along the back of the liner lbut alsol along one or both sides there of. Moreover, the evaporating portion I0 may be arranged along the top of the liner, and the evaporating portion II may also extend along the bottom of the liner. As indicated in the drawing, the evaporator portion I0 includes a smaller amount of larger diameter tubing than the evaporating portion II. The evaporating portion I0 operates at a temperature below the freezing point of water and has a substantially larger refrigerating capacity than the evaporating portion I I. The evaporating portion II operates at a temperature above the freezing point of water and has a capacity sufficient to refrigcrate the food storage compartment to a temperature in the order of F. where the ambient temperature does not exceed 70 F. and under no load conditions. This arrangement of evaporators of different refrigerating capacities in the particular locations relative to the food storage compartment is described and broadly claimed in my application, Serial No. 29,124, filed concurrently with the present'application and assigned to the same assignee.

Liquid refrigerant is supplied from the condensing portion I2 through a conduit I3 to a reservoir I4. From the reservoir I4 liquid refrigerant may flow through a conduit I5 to the evaporating portion I I or through a conduit I6 to the evaporating portion III. Vaporized refrigerant is returned to the condensing portion I 2 from the evaporating portion II through a conduit I'I and vaporized refrigerant from the evaporating portion I0 flows to the condensing portion I2 through a conduit I8. Flow of vaporized refrigerant through the conduit I1 is controlled by a solenoid-operated valve I9. This valve is normally open, and may be closed through operation of a thermostat 20, which lis arranged near the top of the access opening of the food storage compartment 4. The thermostat is thus affected promptly by door openings, which result in an increase in the temperature of the air in this region of the compartment. 'I'he thermostat 20 is shown in the form of a bimetallic strip which, under the proper temperature conditions, bends to bring the contacts 2|, 22 into engagement. This closes the circuit of a coil 23 which operates the solenoid valve I9. Power for the coil 23 is supplied from any suitable source through lines 24, 2,5. Although the thermostat has been shown in the form of a bimetallic strip it is obvious that other conventional types of thermostats may be employed for closing the circuit of coil 23. For example, a feeler bulb may be located in the food storage compartment 4 near the top of the access opening thereof and this bulb may be connected by a tube to a bellows for closing the cir` cuit to the coil 23.

The operation of the refrigerating system will now be described, referring to Fig. 2. As pointed out above, the evaporating portion I I is designed to handlesumcient refrigerant to cool the food 4 of about 40 F. under no load conditions and with an ambient temperature of about 70 F. When these conditions prevail liquid refrigerant from the condensing portion I2 flows through the conduit Il to the reservoir I4. Liquid refrigerant passes from the reservoir through the conduit I5 to the evaporating portion II. vaporized refrigerant from the evaporating portion II passes through the conduit I1 and the open valve I9 to the condensing portion I2, where the vaporized refrigerant is condensed, completing the cycle, Under these conditions no refrigerant passes to the evaporating portion I0 since the I end of the conduit I6, which is provided for carfrigerant to flow into the conduit I6. Since thev evaporating portion I I operates at a temperature above the freezing point of water a high relative humidity is maintained in the food storage compartment 4, thereby minimizing the drying out of foods stored therein.

Should the ambient temperature rise above 70 F. or should an additional load be imposed on the refrigerating system because of freqent door yopenings or the placing of an additional food load in the food storage compartment 4, the refrigeration requirements exceed the capacity of the evaporating portion I I. Under these conditions the temperature in the food storage compartment, and particularly the temperature at the top of the access opening thereof, rises above the predetermined maximum temperature for which the thermostat 20 is set. The thermostat 20 then closes the contacts 2|, 22, energizing the coil 23 to close the valve I9. This prevents the return of vaporized refrigerant from the evaporating portion II to the condensing portion I2 and causes a backing up of liquid refrigerant into the reservoir I4. Ultimately the level of liquid refrigerant in the reservoir AI4 reaches the top of the conduit I '8 and liquid refrigerant is then supplied to the evaporating portion III. The evaporating portion I0 is composed of tubing of a larger diameter than the evaporating portion I I and is able to handle a much larger amount of refrigerant. 'Ihe evaporating'portion I0 thus operates at a, temperature below the freezing point of water and has a capacity suilicient to refrigerate the food storage compartment 4 where the ambient temperature may be of the order of F. and where a heavy load is imposed on the refrigerator. Were the food storage compartment 4 to be refrigerated by the evaporating portion II alone under these conditions an excessively high humidity would result in the food storage compartment, this excessively high humidity condition being aggravated, of course, by the frequent door openings and by the moisture content of additional food placed in the compartment. A substantial amount of sweating in the interior of the refrigerator and of condensation of moisture on foods stored therein might result. However, by utilizing the evaporating portion III which operates at a temperature below the freezingr point of water such excessive humidity and sweating is avoided. Moisture in the air in the food storage compartment 4 condenses on uid refrigerant to the evaporating portion IIl.y

The frost formed on the liner then melts and the water flows iown the back of the liner and is discharged from the food storage compartment through a drain 26 into any suitable receptacle (not shown). Any excessive moisture present in the airwithin the food storage compartment because of door openings, placing of additional food load in the compartment, and high ambient temthe liner of the compartment yin the area of the tho level of the conduit w at its connection to the condensing portion I2, and liquid refrigerant -then flows to the evaporating portion III. The

operation of this system is otherwise the same as that of the system described in connection with 2. v In the refrigerating system shown in Fig. 5 a

solenoid valve I9' is arranged to direct liquid perature is thus removed from the compartment. f

It can be seen, therefore, that by my arrangement a desirable high humidity is maintained in the food storage compartment during low ambient temperature, no load conditions and any excessively high humidity under high ambient temperature, heavy load conditions is avoided. Further, this maintenance of proper humidity conditions is achieved automatically by placing one or the other of the two evaporating portions in operation.

Referring now to Fig. 3, the arrangement there illustrated differs from that shown in Fig. 2 only in that the valve I9 is arranged in the conduit I5 which supplies liquid refrigerant to the evaporating portion I I instead of the conduit I'I which returns vaporized refrigerant from the evaporating portion II to the condensing portion I2. Thev operation is similar to that described in connection with Fig. 2, closing of the valve I 9 resulting in a blocking of the passage of liquid refrigerant through the conduit I5 and a consequent raising of the level of liquid refrigerant in the reservoir I4.

In Fig. 4 there is illustrated an arrangement wherein the condensing portion I2\ also serves the function of a reservoir from which the liquid refrigerant may be directed to either the evaporatingportion I0 or the evaporating portion II. As the vaporized refrigerant condenses in the inclined condensing portion I2 it flows -to the lower end thereof. The liquid line I5' leading to the evaporating portion II is connected to the condensing portion I2 near the bottom thereof.

The liquid line I6' which carries liquid refrigerant to the evaporating portion I0 is connected to the condensing portion I2 some distance above the bottom of the condensing portion I2. Accordingly, under low ambient temperature, no load conditions, where the valve I9 is occupying its normally open position, liquid refrigerant is preferentially supplied to the conduit I5' and thence to the evaporating portion II. The level of the liquid refrigerant in the condensing portion I2 does not reach the opening of the conduit I8. Where higher ambient temperature conditions or heavy loads result in an increase in temperature within the compartment 4 above a predetermined maximum and a consequent closing of the valve I9, flow of liquid refrigerant through the conduit I5 is blocked. Consequently, the level of liquid refrigerant in the lower end of the condensing portion I2 reaches 'portion I I.

refrigerantl positively to either the evaporating portion III or the evaporating portion II. o A valve element 21 is normally positioned by gravity to. close the passage through the conduit I6 to the evaporating portion III and to open the passage through the conduit I5 to the evaporating Thus under low ambient temperature, no load conditions the liquid refrigerant passes from the condensing portion I2 through the conduit I3 to the solenoid valve` I9' and thence through the conduit I5 to the evaporating portion II. Under high ambient temperature or heavy load conditions which result in an increase in the temperature of the air in the compartment 4 the coil 23' is energized to lift the valve element 21 for closing the passage to the conduit I5 and opening the passage to the conduit I6. Liquid refrigerant is then supplied to the evaporating portion I0 until the temperature of the air in the compartment 4 has been satisfactorily lowered.

The arrangement of the evaporating portions I0 and II is designed to secure a low temperature gradient between the top and bottom of the compartment 4. Thus the evaporating portion II which operates above the freezing point of water and hence not far below the temperature of about 40 F. maintained in the food storage compartment is placed along the lower portion of the liner. This gives a minimum convection of air within the compartment 4, and such-minimum convection is suilicient to maintain the desirable low temperature gradient since the difference between the evaporator temperature and the temperature of the air in the compartment 4 is small. On the other hand the evaporating portion I0 which operates at a temperature below the freezing point of water and hence at a temperature differing substantially from that normally maintained in the compartment 4 is arranged along the upper portion of the liner 5. The air cooled by the evaporating portion In at the upper portion of the compartment 4 tends to descend to the bottom of the compartment and a maximum convection is achieved. This maximum convection assists in maintaining a. low temperature gradient between the topvand bottom of the compartment 4.

While I have shown and described specific embodimentsof my invention as applied to a two-temperature household refrigerator, I do not desire my invention to be limited to the particular constructions shown and I intend, by the appended claims, to cover all modifications within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

' l. Refrigerating apparatus including a cabinet having a food storage compartment, a liner for said food storage compartment, a first evaporator secured to the lower'portion of said liner for refrigerating said food storage compartment, a second evaporator secured to the upper portion of said liner for directly refrigerating said -compartment, means including a refrigerant condensing unit for supplying refrigerant to said first evaporator` for operation at a temperature high humidity in said compartment, means responsive to a predetermined temperature within said food storage compartment for discontinuing refrigeration by said first evaporator, and means rendered effective only upon discontinuation of refrigeration by said first evaporator for directing refrigerant to said second evaporator.

2. Refrigerating apparatus including a cabinet having a food storage compartment, a liner for said food storage compartment, a secondary refrigerating system, said secondary refrigerating system including two evaporating portions, one

of said evaporating portions being secured to the lower portion of said liner, means including a condensing portion for supplying refrigerant to said one of said evaporating portions for operation at a temperature above the freezing point of water, the other of said evaporating portions being secured to the upper portion of said liner,

means including said condensing portion for supplying refrigerant to said other of said evaporating portions for operation at a temperature below the freezing point of water, a reservoir for liquid refrigerant, means for conducting liquid refrigerant from said condensing portion to said reservoir, means for conducting refrigerant from said reservoir to said one of said-evaporating portions, means responsive to a predetermined temperature within said food storage compartment for preventing flow of refrigerant through said one of said evaporating portions, and means rendered effective when flow of refrigerant through said one of said evaporating portions is prevented for delivering refrigerant from said reservoir to said other of said evaporating portions.

3. Refrigerating apparatus including a cabinet having a food storage compartment, a4 liner lfor said food storage compartment, a first evaporator secured to the lower portion of said liner for refrigerating said food storage `compartment, means including a refrigerant condensing unit for supplying refrigerant to said first evaporator for operation at a temperature above the freezing point of water. a second evaporator secured to the upper portion of said liner yfor refrigerating said compartment, means including said refrigerant condensing unit for supplying refrigerant to said second evaporator for operation at a temperature below the freezing point of water, a reservoir for liquid refrigerant, a first liquid line opening into said reservoir for conducting liquid refrigerant from said reservoir to said first evaporator, a second liquid line opening into said reservoir for conducting liquid refrigerant from said reservoir to said second evaporator, said first liquid line opening into said reservoir at a lower level than said second liquid line whereby liquid refrigerant is preferentially supplied through said first liquid line to said first evaporator, and means responsive to a predetermined temperature within said compartment for preventing flow of refrigerant through said first evaporator, the operation of said last-mentioned means affording accumulation of liquid refrigerant in said reservoir to raise the level of liquid refrigerant therein whereby liquid refrigerant is supplied through said second liquid line to said second evaporator.

4. Refrigerating apparatus including a cabinet having a food storage compartment, a liner for said food'storage compartment,- a first evaporator secured to the lower portion of said liner for refrigerating said compartment, means including a refrigerant condensing unit for supplying refrigerant to said first evaporator for operation at a temperature above the freezing point of water, a second evaporator secured to the upper portion of said liner for refrigerating said compartment, means including said refrigerant condensing unit for supplying refrigerant to said second evaporator for operation at a temperature below the freezing point of water, a reservoir for liquid refrigerant, a first liquid line opening into said reservjoir for conducting liquid refrigerant from said reservoir to said first evaporator. a second liquid line opening into said reservoir forconducting liquid refrigerant from said reservoir to said second evaporator, said first liquid line opening into saidreservoir at a lower level than said second liquid line whereby liquid refrigerant is preferentially supplied to said first evaporator, a valve in said first liquid line for controlling the flow of refrigerant to said first evaporator, and means responsive to a predetermined temperature within said compartment for closing said valve, the closing of said valve affording accumulation of liquid refrigerant in said reservoir to raise the level of liquid refrigerant therein whereby liquid refrigerant is supplied to said second evaporator.

5. Refrigerating apparatus including a cabinet having a food storage compartment, a liner for said food storage compartment, a first evaporator secured to the lower portion of said liner for refrigerating said food storage compartment, means including a refrigerant condensing unit for supplying refrigerant to said first evaporator for operation at a temperature above the freezing point of water, a second evaporator secured to the upper portion of said liner for refrigerating said compartment, means including said refrigerant condensing unit for supplying refrigerant to said second evaporator for operation at a temperature below the freezing point of water, a reservoir for liquid refrigerant, a first liquid line opening into said reservoir for conducting liquid refrigerant from said reservoir to said first evaporator, a second liquid line opening into said reservoir for conducting liquid refrigerant from said reservoir to said second evaporator, said first liquid line opening into said reservoir at a lower level than said second liquid line whereby liquid refrigerant is preferentially supplied to said first evaporator, a first vapor line for conducting vaporized refrigerant from said first evaporator, a second vapor line for conducting vaporized refrigerant from said second evaporator, a valve in said first vapor line for controlling flow of vaporized refrigerant therethrough, and means responsive to a predetermined maximum temperature within said compartment for closing said valve to prevent fiow of vaporized refrigerant through said first vapor line, the closing of said valve affording accumulation of liquid refrigerant in said reservoir to raise the levelof liquid refrigerant therein whereby liquid refrigerant is supplied from said reservoir to said second evaporator.

- 6. Refrigerating apparatus including a cabinet having a food storage compartment, a liner for said food storage compartment, a secondary refrigerating system including two evaporating portions for refrigerating said compartment, one of said evaporating portions being secured to thel lower portion of said liner, the other of said evaporating portions being'secured to the upper portion of,l saidliner, means including a condensing portionfor supplying refrigerant to said one of said evaporating portions for operation at a temperature above' the freezing point of water, means incl-uding said condensing portion for supplying refrigerant to said other of said evaporating portions Vfor operation ata temperature below the freezing point of Water, a reservoir for liquid refrigerant, means for conducting liquid refrigerant from said condensing portion to said reservoir. a first liquid line opening into said reservoir for conducting liquid refrigerant from said reservoir to said one of said evaporating portions, a second liquid line opening into' said reservoir for conducting liquid refrigerant from said reservoir to said other of said evaporating portions, said first liquid line opening into said reservoir at a lower level than said second liquid line whereby liquid refrigerant is preferentially supplied to said one of said evaporating portions, a valve in said first liquid line for controlling the ow of refrigerant to said rst of said evaporating portions, and means responsive to a predetermined maximum temperature within said compartment for closing said valve, theL closing of said valve affording accumulation of liquid refrigerant in said reservoir to raise the level of liquid refrigerant therein whereby liquid refrigerant is supplied to said other of said evaporating portions.

7. Refrigerating apparatus including a cabinet having a food storage compartment, a liner 'for said food 'storage compartment, a secondary refrigerating system including two evaporating portions for refrigerating said compartment, one

of said evaporating portions being secured to the lower portion of said liner, the other of said evaporating portions being secured to the upper portion of said liner. means including a condensing portion for supplying refrigerant to said one of said evaporating portions for operation at al temperature above the freezing point of water, and for supplying refrigerant to said other of said evaporating portions for operation at a ternperature below the freezing point of water, a reservoir for liquid refrigerant, means for conducting liquid refrigerant from said condensing portion to said reservoir, a rst liquid line opening into said reservoir for conducting liquid refrigerant from said reservoir to said one of said evaporating portions, a second liquid line open-V ing into said reservoir for conducting liquid refrigerant to said other of said evaporating portions, said rst liquid line opening into said reservoir at a lower level than said second liquid line whereby liquid refrigerant is preferentially supplied to said one of said evaporating portions, a first vapor line for returning vaporized refrigerant f-rom said one of said evaporating portions to said condensing portion, a, second vapor line for returning vaporized refrigerant from said other of said evaporating portions to said condensing portion, a valve in said first vapor line for preventing return of vaporized refrigerant to said condensing portion from said one of said evaporating portions, and means responsive to a predetermined maximum temperature within said compartment vfor closing said valve, the closing of said valve affording accumulation of liquid refrigerant in said reservoir to raise the level of liquid refrigerant therein whereby liquid refrigerant is supplied from said reservoir to said other of said evaporating portions.

8. Refrigerating apparatus including a cabinet having a food storage compartment, a secondary refrigerating system for cooling said compart- -ment, said secondary system comprising a condensing portion and two evaporating portions, said condensing portion being inclined to direct condensed refrigerant to the lower end thereof, a first liquid line opening into said condensing portion for supplying liquid refrigerant to one of said evaporating portions, a second liquid line opening into said condensing portion for supplylng liquid refrigerant to the other of said evaporating portions, said first liquid line opening into said condensing portion at a lower level than said second liquid line whereby liquid refrigerant is preferentially supplied to said one of said evaporating portions, and a valve for controlling flow of refrigerant through said one of said evaporatingfportions, said valve being actuated to itsclosed position in response to a predetermined maximum temperature within said compartment, the closing of said valve' affording accumulation of liquid refrigerant in said condensing portion to raise the level of liquid refrigerant therein whereby liquid refrigerant is supplied from said condensing portion to said other of said evaporating portions.

9. Refrigerating apparatus including a cabinet having a food storage compartment, a liner for said food storage compartment, a secondary refrigerating system for cooling said compartment, said secondary system including a condensing portion and two evaporating portions, one of said evaporating portions being secured to the lower portion of said liner and including a substantial length of tubing of relatively small diameter, the other of said evaporating portions bein-g secured to the upper portion of said liner and including a smaller length of tubing of substantially greater diameter than said one of said evaporating portions, a reservoir for liquid refrigerant, a conduit for supplying liquid refrigerant from said condensing portion to said reservoir, means for supplying liquid refrigerant from said reservoir to said one of said evaporating portions, means responsive to a predetermined maximum temperature Within said compartment for preventing flow of refrigerant through said one of said evaporating portions, and means dependent upon the prevention of flow .of refrigerant through said one of said evaporating portions for eecting delivery of refrigerant from said reservoir to said other of said evaporating portions.

l0. Refrigerating apparatus including a refrigerator having a food storage compartment. a liner for said food storage compartment, a irst evaporator secured to the lower portion of said liner for refrigerating said food storage compartment, means including a refrigerant condensing unit for supplying refrigerant to said first evaporator for operation at a temperature above the freezing point of water, a second evaporator secured to the upper portion of said liner for directly refrigerating said compartment, means including said refrigerant condensing unit for supplying refrigerant to said second evaporator for operation at a temperature below the freezing f point of water, and a solenoid-operated valve energized in response to a predetermined maximum temperature within said storage compartment for discontinuing refrigeration by'said rst evaporator and for simultaneously directing refrigerant to said second evaporator.

11. Refrigerating apparatus including a refrigerator having a food storage compartment. a liner for said food storage compartment, a secondary refrigerating system, said secondary sysx dii tem including two @vapor-ating portions, one of said evaporating portions being secured to lower portion oi said liner, means including a condensing portion for supplying refrigerant to said one of said evaporating portions for 010eration at a temperature above the freezing point of water, the other of said evaporating portions being secured to the upper portion of said liner, means including said condensing portion for supplying refrigerant to said other of said evap- 1 orating portions for operation at a temperature below the freezing point of water, means for conducting refrigerant from said condensing portion, a solenoid-operated valve disposed between said last-mentioned means and said evaporating portions for directing refrigerant alternatively to either of said evaporating portions, said valve preferentially directing refrigerant to said one of said evaporating portions, and means responsive to a. predetermined maximum temperature within i2 said compartment for actuating said valve 'to di rect refrigerant to said other of said evaporating portions,

LA MAR S. COOPm.

REFERENCES CITED The foiowins references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,146,796 Dasher Feb. 14, 1939 2,292,405 Reeves Aug. 11, 1942 2,312,861- Atchison Mar. 2, 1943 2,386,919 Tobey -s Oct. 16, 1945 2,416,777 Schweller Mar. 4, 1947 2,426,578 Tobey Aug. 26. 1947 2,434,361 Iwashita June 13. 1948 2,455,859 Atchison Dec. 7, 1948 2,471,137 Atchison Mar 24. 1949I 

